@MikeMillerGIS was kind enough to modify his arcade expression which was originally suggested by HungGi.
Mike's expression (listed below) was able to do what I needed and will help out going forward with working on migrating dimension annotation to labels. All I needed to do was replace the "LineFC" with my line feature class, then insert the expression in the Calculate Field on my point feature class. I can use this info to assign the label position so that the label remains consistent with the side of the parcel line where the annotation was located.
// The Road Centerline feature set
var line_class = FeatureSetByName($datastore, "LineFC", ["OBJECTID"], true);
// ************* Functions *************
function find_closest_line() {
// Find closest line segment to $feature. Limit search to specific radius.
var candidates = Intersects(line_class, Buffer($feature, 30, "feet"));
var shortest = [1e10, null];
for (var line in candidates) {
var d = Distance($feature, line)
if (d < shortest[0]) shortest = [d, line]
}
return shortest[-1]
}
function return_side_of_Line(point_feature, line_feature) {
/*
finds the closest point on line_feature from point_feature
Args:
point_feature: Point Geometry
line_feature: Line Geometry
Returns: dictionary
{distance: number, // distance from point_feature to closest point
coordinates: array, // the coordinate pair of the closest point
isVertex: bool, // if the closest point is a vertex of line_feature
lineSide: text} // side of the line that point_feature is on based
*/
var point_feature = Geometry(point_feature);
var line_feature = Geometry(line_feature);
var vertices = line_feature["paths"]
var x = point_feature["x"];
var y = point_feature["y"];
// Loop through each part of the geometry and each segment, tracking the shortest distance
var shortest = [1e10];
for (var i in vertices) {
var part = vertices[i];
var previous = part[0];
for (var j = 1; j < Count(part); j++) {
var current = part[j];
var result = pDistance(x, y, previous["x"], previous["y"], current["x"], current["y"]);
if (result[0] < shortest[0]) shortest = result
previous = current;
}
}
// Couldn't find anything
if (Count(shortest) == 1) return null
return shortest[3]
}
function pDistance(x, y, x1, y1, x2, y2) {
// adopted from https://stackoverflow.com/a/6853926
var A = x - x1;
var B = y - y1;
var C = x2 - x1;
var D = y2 - y1;
var dot = A * C + B * D;
var len_sq = C * C + D * D;
var param = -1;
if (len_sq != 0) //in case of 0 length line
param = dot / len_sq;
var xx, yy;
var is_vertex = true;
if (param < 0) {
xx = x1;
yy = y1;
}
else if (param > 1) {
xx = x2;
yy = y2;
}
else {
is_vertex = false;
xx = x1 + param * C;
yy = y1 + param * D;
}
var dx = x - xx;
var dy = y - yy;
return [Sqrt(dx * dx + dy * dy), [xx, yy], is_vertex, side_of_line(x,y,x1,y1,x2,y2)];
}
function side_of_line(x, y, x1, y1, x2, y2) {
// get side of line segment that a point (x, y) is on based on the direction of segment [[x1, y1], [x2, y2]]
// adopted from https://math.stackexchange.com/a/274728
var d = (x - x1) * (y2 - y1) - (y - y1) * (x2 - x1)
if (d < 0) {
return 'left'
} else if (d > 0) {
return 'right'
} else {
return null
}
}
// ************* End Functions Section ******************
// find closest line to $feature
var closest_line = find_closest_line();
if (closest_line == null) return
// find info about the closest point on the closest line to $feature
var side_line = return_side_of_Line($feature, closest_line);
if (side_line == null) return
return side_line
